mysql insert ignore

is equivalent to or in MySQL, so why in is recommended, in is a bit like this: 1. The In operator syntax is clearer and more intuitive when using the long legal option list; 2. When using in, The order of calculation is easier to manage (because fewer operators are used); the 3.in operator is generally faster than the OR operator manifest, and 4.index is a bit more likely to contain other SELECT statements, which makes it possible to create a

Original: Two easy-to-ignore MySQL knowledgeWhy does the title have to be named? Commen sence refers to things everyone should know, but often people will be slightly more of these things, or to these things smattering, today I summarize my own in MySQL encountered some commen sense types of problems.1, varchar (5) How many Chinese characters can be stored, how m

1. Null is not comparable (similar to Nan in Java), so its comparison operation is always false such as:Update table Set channel = #channel # where order_id = 12345 and Channel 2. Count distinct Bug:select count (distinct three_part_extend) from Table_order where three_part_extend are not null and th Ree_part_extendSee details: http://dinglin.iteye.com/blog/1976026 http://dinglin.iteye.com/blog/1982176Issues that are easy to ignore in

Tags: end ignores gen Sele from @age BSP Query agent ☆1. Q.ques_group passed in as null or"'do not query for this condition: value="SELECT * fromQuestion QWHERE 1=1 and(Q.ques_group=: Quesgroupor: Quesgroup is NULL or: Quesgroup="') andQ.type=: Type ",1: (Q.ques_group=: Quesgroupor: Quesgroup is NULL or: Quesgroup="') 2: (Q.ques_group= ISNULL(: Quesgroup, Q.ques_group)ORQ.ques_group=( Case when: Quesgroup= "' ThenQ.ques_groupELSE: QuesgroupEND): Decomposition:SELECT *

Insert a new column after specifying a column in MySQL, and insert a column in mysql.ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_nameAlter_specification [, alter_specification]...Alter_specification:Table_options| ADD [COLUMN] col_name column_definition[FIRST | AFTER col_name]| ADD [COLUMN] (col_name column_definition

Mysql technology insider InnoDB Insert (Insert) operation, mysqlinnodb What is the internal reaction of an innodb table after the client sends an insert command? This article will reveal this story to everyone. Of course, I am not very easy to learn. If you find anything wrong, you can point it out and discuss it toge

How does mysql optimize insert record speed and mysql optimize insert When a record is inserted, index, Uniqueness check, and the number of records inserted at a time are mainly affected. Based on these conditions, you can optimize the insert record speed. This section desc

, Replace the row with the same data (that is, the direct original value overrides). Multi-line replace empty table--use "Replace INSERT into ... VALUES (..), (..), (..), ... "To insert data into an empty table. insert-duplicate--using INSERT into. VALUES (..), (..), (..), ... On DUPLICATE KEY UPDATE ... "The s

MySQL general registration insert optimization ., Mysql registration insert Optimization The common practice is: The user registers with the mobile phone number. By default, the user table is queried Based on the mobile phone number to see if the mobile phone number is available. If yes, the system prompts that the use

MySQL batch insert data script, mysql insert script MySQL batch insert data script #! /Bin/bashi = 1; MAX_INSERT_ROW_COUNT = $1; while [$ I-le $ MAX_INSERT_ROW_COUNT] do mysql-uroot-p

Five methods for MySQL to insert Chinese characters without garbled characters, and five methods for mysql to insert garbled characters Method 1:Log on to MySQL, first set names latin1, and then execute the SQL statement in the update statement or

| MySQL insert user error. mysql insert When you add a user using insert, an error may be returned: ERROR 1364 (HY000): Field 'ssl _ cipher 'doesn' t have a default value The my-default.ini has a statement: SQL _mode = NO_ENGINE_SUBSTITUTION, STRICT_TRANS_TABLES Strict

InnoDB Insert (Insert) operation (II)-mysql technology insider, innodb-mysql I want to prove the relationship between the mysql innodb Storage engine, commit operations, and flush data to the disk. After talking with colleagues, he said, you should take the innodb_buffer_s

Tags: padding val bool span syntax takes time option offUse the INSERT INTO SQL statement in the MySQL table to insert the data. You can insert data into a data table by mysql> the command Prompt window, or insert data through a

Tags: Tool constraints nbsp Toolbar content Create physical not stsAbsrtact: We often need to make a bulk insert of SQL, which requires that the record does not exist and is inserted, and the presence is not inserted. What if an INSERT statement is used? Normal Insert into insert: INSERTINTOcard(cardno,cardnum)VALUES(

MySQL study Notes-insert row records into data tables 1. use the INSERT statement to INSERT new data Syntax: INSERT [INTO] tbl_name [(col_name,...)] VALUES (pression ,...),... INSERT [INTO] tbl_name SET col_name = expression ,...

Recently I used a very simple and easy-to-use method to solve the insert throughput problem in the business. Here I will summarize it. First, let's clarify that the insert throughput is not the IPS (insert per second), but the RPS (effect rows per second ). Next, let's talk about batch insert. In fact, as the name sug

. checkErrorPacket (MysqlIO. java: 3814)At com. mysql. jdbc. MysqlIO. sendCommand (MysqlIO. java: 2478)At com. mysql. jdbc. MysqlIO. sqlQueryDirect (MysqlIO. java: 2625)At com.mysql.jdbc.ConnectionImpl.exe cSQL (ConnectionImpl. java: 2547)At com.mysql.jdbc.StatementImpl.exe cuteUpdateInternal (StatementImpl. java: 1541)At com.mysql.jdbc.StatementImpl.exe cuteLargeUpdate (StatementImpl. java: 2605)At com.mys

1. Insert data to derive from other tables Table A has ID, cola fieldTable B has ID, cola, colb ... Fields, where the IDs are all primary keys, cola as columns of the same nameNow you want to insert the colb>1000 records from Table B in Table A, which the SQL statement can write: Copy Code code as follows: Insert into A (Id,cola) Select Id,cola fr

If you specify on DUPLICATE key UPDATE and the insert row causes duplicate values to occur in a unique index or primary key, the Row old row update. For example, if column A is defined as unique and contains a value of 1, the following two statements have the same effect: The code is as follows: The code is as follows Copy Code mysql> INSE